CB1 and CB2 receptor mRNA expression in human peripheral blood mononuclear cells (PBMC) from various donor types

Marijuana cannabinoid receptors (CBR), CB1 and CB2, are G protein-coupled receptors reported to be expressed in brain as well as cells of the periphery. Human peripheral blood mononuclear cells (PBMCs) are reported to express CBR mRNA with CB2 expression higher than CB1 and expression in B cells higher than other cells. However, it is not known if the mRNA expression is constant among individuals of differing ages, gender, or ethnic origins. In the present study, PBMCs were obtained from a limited number of normal donors of both genders, of ages ranging from 21 to 55, and from Caucasian, and Asian ethnic origin. Using semi-quantitative RT-PCR, we confirmed previous reports that CB2 mRNA expression was higher than CB1 in PBMCs and in addition demonstrated that this basic profile was observed when stratified by age, gender, or ethnic origin. The latter results suggest that CBR expression is relatively constant across the human population.